The final fungicide application on winter barley may be applied anytime between GS39 and GS45 for best results. This is from the time the full flag leaf is visible until just before the head appears.
Chlorothalonil at a rate of 1L/ha should be applied in all final sprays on barley to prevent ramularia and also as part of an anti-resistance strategy to protect the other chemistry.
An SDHI should be applied, particularly where crops are in a two-spray programme and have not yet received an SDHI. It is also important to remember to alternate triazoles between spray timings.
If an SDHI is not applied, a strobilurin will provide protection against net blotch.
Plant growth regulator
The opportunity may still be there to apply plant growth regulator at the final spray timing. Think about your rates. Barley is about half the height now that it will be once it reaches its peak.
If you are considering reducing the rate of growth regulator take into account how your crop has been managed so far this season as regards fertiliser application.
Depending on the product, the latest timing of application will vary between flag leaf and awns peeping.